1. Field of the Invention
The present invention relates to machines for applying, to items, labels which are distributed uniformly on a wound strip, comprising, mounted on a support plate, a swinging arm for detecting the items, a drum for driving the strip, the drum being rotated stepwise by a drive device, means of controlling the drive device, means of detecting the angular movement of the arm, and means, associated with the arm and controlled by the movement of the strip, of transferring the labels from the strip onto the corresponding items.
The invention applies more particularly to automatic machines intended to apply labels to items of varying shape, especially fruit or vegetables.
2. History of the Related Art
A machine of this kind is described, for example, in patent application FR-A-2,619,079. In this application, a lever connected by one of its ends to the detection arm acts directly on a solenoid valve that controls the drive device.
In these machines, which are placed in packaging stations or are portable and used manually, an item passing under the detection arm acts so as to raise this arm and the means of detecting the movement of the arm trigger, via the control means, the driving of the strip and the application of a label to the item detected.
However, in current machines, the detection arm needs to be moved through quite a large angle to trigger the labelling of the item which means that when placed in packaging stations, these machines are not capable of labelling all the items that raise the arm.
What is more, the manual use of these machines requires a certain amount of physical strength to be able to trigger labelling of all the items, and these machines therefore do not allow labelling at a high rate.
Furthermore, when the drive device comprises a ratchet wheel operated by a member that moves back and forth, especially one that consists of a rod connected, for example, to the piston of a pneumatic ram or to the plunger of an electromagnet, the detection arm has to fall back through quite a large angle to cause the rod to return to the position in which it is ready for labelling, which means that these machines are not capable of labelling two items which are close together, and this further limits the labelling rate for any type of use.